Field of Invention
The invention concerns a magnetostrictive displacement sensor.
A magnetostrictive displacement sensor comprises a magnetostrictive material made of wave-guide, as a rule filamentary or cannular, extending in the measuring direction, in particular linearly. By a position magnet, in particular brought without contact beside the wave-guide, by the magnetic fields interference there is produced a mechano-elastic wave which is spreading in those two directions along the wave-guide guide to be detected at its end. Because of the predefined propagation time there can be determined the precise distance of the position magnet in respect of the end of the wave-guide and thereby the position of a mobile constructive unit the position magnet is attached to.
As to the assemblage, from EP 0 882 212 there is for example known the inserting of the wave guide into a support body, for example a tube, and the terminal plate into a specific housing connected to the support body at one of its ends. Since firstly the passing between the support body and this terminal plate has to be conceived very stable from a mechanical point of view too, to the previous constructions this objective was accomplished in that the terminal plate housing was surrounding in the exterior the support body in its terminal area.
But this thing raised the costs and thereby the manufacturing price of the sensitive element.
Supplementary, there can be discarded too a separate coating of the terminal plate in the shape of a completely closing housing, in particular having its own stability, since this sensitive element—due to the fact that the support body has a limited stability too—will always be included into a considerably more stable protective housing, for example into a protective profile, by having the support body of the sensitive element inserted, whereupon this protective profile always changes its shape according to the employing situation and can be directly made too from parts of the constructive element whose position is to be determined.
An ideal shape of such a stable protective profile is a protective profile as flattened as possible to have it arranged on the surfaces of another constructive element without occupying a great supplementary volume.
On the assemblage costs an important role is played by the correlation among the Villary tape, the wave guide and the detection coil as well as their arrangement on or into the terminal plate respectively since the Villary tape has to be positioned with a console free overhang from the wave guide through the center of the detection coil orifice and by touching the effect can already be influenced.